7 files changed, 520 insertions, 7 deletions

diff --git a/Documentation/pm_qos_interface.txt b/Documentation/pm_qos_interface.txt
new file mode 100644
index 000000000000..49adb1a33514
--- /dev/null
+++ b/Documentation/pm_qos_interface.txt
@@ -0,0 +1,59 @@
+PM quality of Service interface.
+
+This interface provides a kernel and user mode interface for registering
+performance expectations by drivers, subsystems and user space applications on
+one of the parameters.
+
+Currently we have {cpu_dma_latency, network_latency, network_throughput} as the
+initial set of pm_qos parameters.
+
+The infrastructure exposes multiple misc device nodes one per implemented
+parameter.  The set of parameters implement is defined by pm_qos_power_init()
+and pm_qos_params.h.  This is done because having the available parameters
+being runtime configurable or changeable from a driver was seen as too easy to
+abuse.
+
+For each parameter a list of performance requirements is maintained along with
+an aggregated target value.  The aggregated target value is updated with
+changes to the requirement list or elements of the list.  Typically the
+aggregated target value is simply the max or min of the requirement values held
+in the parameter list elements.
+
+From kernel mode the use of this interface is simple:
+pm_qos_add_requirement(param_id, name, target_value):
+Will insert a named element in the list for that identified PM_QOS parameter
+with the target value.  Upon change to this list the new target is recomputed
+and any registered notifiers are called only if the target value is now
+different.
+
+pm_qos_update_requirement(param_id, name, new_target_value):
+Will search the list identified by the param_id for the named list element and
+then update its target value, calling the notification tree if the aggregated
+target is changed.  with that name is already registered.
+
+pm_qos_remove_requirement(param_id, name):
+Will search the identified list for the named element and remove it, after
+removal it will update the aggregate target and call the notification tree if
+the target was changed as a result of removing the named requirement.
+
+
+From user mode:
+Only processes can register a pm_qos requirement.  To provide for automatic
+cleanup for process the interface requires the process to register its
+parameter requirements in the following way:
+
+To register the default pm_qos target for the specific parameter, the process
+must open one of /dev/[cpu_dma_latency, network_latency, network_throughput]
+
+As long as the device node is held open that process has a registered
+requirement on the parameter.  The name of the requirement is "process_<PID>"
+derived from the current->pid from within the open system call.
+
+To change the requested target value the process needs to write a s32 value to
+the open device node.  This translates to a pm_qos_update_requirement call.
+
+To remove the user mode request for a target value simply close the device
+node.
+
+
+
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index d2fabe7863a9..2a98d99cbd46 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -12,7 +12,7 @@
 #include <linux/mutex.h>
 #include <linux/sched.h>
 #include <linux/notifier.h>
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 #include <linux/cpu.h>
 #include <linux/cpuidle.h>
 
@@ -265,7 +265,10 @@ static struct notifier_block cpuidle_latency_notifier = {
         .notifier_call = cpuidle_latency_notify,
 };
 
-#define latency_notifier_init(x) do { register_latency_notifier(x); } while (0)
+static inline void latency_notifier_init(struct notifier_block *n)
+{
+        pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
+}
 
 #else /* CONFIG_SMP */
 
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index eb666ecae7c9..ba7b9a6b17a1 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -14,7 +14,7 @@
 
 #include <linux/kernel.h>
 #include <linux/cpuidle.h>
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 #include <linux/moduleparam.h>
 #include <linux/jiffies.h>
 
@@ -81,7 +81,8 @@ static int ladder_select_state(struct cpuidle_device *dev)
         /* consider promotion */
         if (last_idx < dev->state_count - 1 &&
             last_residency > last_state->threshold.promotion_time &&
-            dev->states[last_idx + 1].exit_latency <= system_latency_constraint()) {
+            dev->states[last_idx + 1].exit_latency <=
+                        pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) {
                 last_state->stats.promotion_count++;
                 last_state->stats.demotion_count = 0;
                 if (last_state->stats.promotion_count >= last_state->threshold.promotion_count) {
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 299d45c3bdd2..78d77c5dc35c 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -8,7 +8,7 @@
 
 #include <linux/kernel.h>
 #include <linux/cpuidle.h>
-#include <linux/latency.h>
+#include <linux/pm_qos_params.h>
 #include <linux/time.h>
 #include <linux/ktime.h>
 #include <linux/hrtimer.h>
@@ -48,7 +48,7 @@ static int menu_select(struct cpuidle_device *dev)
                         break;
                 if (s->target_residency > data->predicted_us)
                         break;
-                if (s->exit_latency > system_latency_constraint())
+                if (s->exit_latency > pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY))
                         break;
         }
 
diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h
new file mode 100644
index 000000000000..2e4e97bd19f7
--- /dev/null
+++ b/include/linux/pm_qos_params.h
@@ -0,0 +1,25 @@
+/* interface for the pm_qos_power infrastructure of the linux kernel.
+ *
+ * Mark Gross
+ */
+#include <linux/list.h>
+#include <linux/notifier.h>
+#include <linux/miscdevice.h>
+
+#define PM_QOS_RESERVED 0
+#define PM_QOS_CPU_DMA_LATENCY 1
+#define PM_QOS_NETWORK_LATENCY 2
+#define PM_QOS_NETWORK_THROUGHPUT 3
+
+#define PM_QOS_NUM_CLASSES 4
+#define PM_QOS_DEFAULT_VALUE -1
+
+int pm_qos_add_requirement(int qos, char *name, s32 value);
+int pm_qos_update_requirement(int qos, char *name, s32 new_value);
+void pm_qos_remove_requirement(int qos, char *name);
+
+int pm_qos_requirement(int qos);
+
+int pm_qos_add_notifier(int qos, struct notifier_block *notifier);
+int pm_qos_remove_notifier(int qos, struct notifier_block *notifier);
+
diff --git a/kernel/Makefile b/kernel/Makefile
index db9af707ff5b..8331243a4e5e 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -9,7 +9,7 @@ obj-y     = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
             rcupdate.o extable.o params.o posix-timers.o \
             kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
             hrtimer.o rwsem.o latency.o nsproxy.o srcu.o \
-            utsname.o notifier.o ksysfs.o
+            utsname.o notifier.o ksysfs.o pm_qos_params.o
 
 obj-$(CONFIG_SYSCTL) += sysctl_check.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
new file mode 100644
index 000000000000..0afe32be4c85
--- /dev/null
+++ b/kernel/pm_qos_params.c
@@ -0,0 +1,425 @@
+/*
+ * This module exposes the interface to kernel space for specifying
+ * QoS dependencies.  It provides infrastructure for registration of:
+ *
+ * Dependents on a QoS value : register requirements
+ * Watchers of QoS value : get notified when target QoS value changes
+ *
+ * This QoS design is best effort based.  Dependents register their QoS needs.
+ * Watchers register to keep track of the current QoS needs of the system.
+ *
+ * There are 3 basic classes of QoS parameter: latency, timeout, throughput
+ * each have defined units:
+ * latency: usec
+ * timeout: usec <-- currently not used.
+ * throughput: kbs (kilo byte / sec)
+ *
+ * There are lists of pm_qos_objects each one wrapping requirements, notifiers
+ *
+ * User mode requirements on a QOS parameter register themselves to the
+ * subsystem by opening the device node /dev/... and writing there request to
+ * the node.  As long as the process holds a file handle open to the node the
+ * client continues to be accounted for.  Upon file release the usermode
+ * requirement is removed and a new qos target is computed.  This way when the
+ * requirement that the application has is cleaned up when closes the file
+ * pointer or exits the pm_qos_object will get an opportunity to clean up.
+ *
+ * mark gross mgross@linux.intel.com
+ */
+
+#include <linux/pm_qos_params.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+
+#include <linux/uaccess.h>
+
+/*
+ * locking rule: all changes to target_value or requirements or notifiers lists
+ * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
+ * held, taken with _irqsave.  One lock to rule them all
+ */
+struct requirement_list {
+        struct list_head list;
+        union {
+                s32 value;
+                s32 usec;
+                s32 kbps;
+        };
+        char *name;
+};
+
+static s32 max_compare(s32 v1, s32 v2);
+static s32 min_compare(s32 v1, s32 v2);
+
+struct pm_qos_object {
+        struct requirement_list requirements;
+        struct blocking_notifier_head *notifiers;
+        struct miscdevice pm_qos_power_miscdev;
+        char *name;
+        s32 default_value;
+        s32 target_value;
+        s32 (*comparitor)(s32, s32);
+};
+
+static struct pm_qos_object null_pm_qos;
+static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
+static struct pm_qos_object cpu_dma_pm_qos = {
+        .requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
+        .notifiers = &cpu_dma_lat_notifier,
+        .name = "cpu_dma_latency",
+        .default_value = 2000 * USEC_PER_SEC,
+        .target_value = 2000 * USEC_PER_SEC,
+        .comparitor = min_compare
+};
+
+static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
+static struct pm_qos_object network_lat_pm_qos = {
+        .requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
+        .notifiers = &network_lat_notifier,
+        .name = "network_latency",
+        .default_value = 2000 * USEC_PER_SEC,
+        .target_value = 2000 * USEC_PER_SEC,
+        .comparitor = min_compare
+};
+
+
+static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
+static struct pm_qos_object network_throughput_pm_qos = {
+        .requirements =
+                {LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
+        .notifiers = &network_throughput_notifier,
+        .name = "network_throughput",
+        .default_value = 0,
+        .target_value = 0,
+        .comparitor = max_compare
+};
+
+
+static struct pm_qos_object *pm_qos_array[] = {
+        &null_pm_qos,
+        &cpu_dma_pm_qos,
+        &network_lat_pm_qos,
+        &network_throughput_pm_qos
+};
+
+static DEFINE_SPINLOCK(pm_qos_lock);
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+                size_t count, loff_t *f_pos);
+static int pm_qos_power_open(struct inode *inode, struct file *filp);
+static int pm_qos_power_release(struct inode *inode, struct file *filp);
+
+static const struct file_operations pm_qos_power_fops = {
+        .write = pm_qos_power_write,
+        .open = pm_qos_power_open,
+        .release = pm_qos_power_release,
+};
+
+/* static helper functions */
+static s32 max_compare(s32 v1, s32 v2)
+{
+        return max(v1, v2);
+}
+
+static s32 min_compare(s32 v1, s32 v2)
+{
+        return min(v1, v2);
+}
+
+
+static void update_target(int target)
+{
+        s32 extreme_value;
+        struct requirement_list *node;
+        unsigned long flags;
+        int call_notifier = 0;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        extreme_value = pm_qos_array[target]->default_value;
+        list_for_each_entry(node,
+                        &pm_qos_array[target]->requirements.list, list) {
+                extreme_value = pm_qos_array[target]->comparitor(
+                                extreme_value, node->value);
+        }
+        if (pm_qos_array[target]->target_value != extreme_value) {
+                call_notifier = 1;
+                pm_qos_array[target]->target_value = extreme_value;
+                pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
+                        pm_qos_array[target]->target_value);
+        }
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+        if (call_notifier)
+                blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
+                        (unsigned long) extreme_value, NULL);
+}
+
+static int register_pm_qos_misc(struct pm_qos_object *qos)
+{
+        qos->pm_qos_power_miscdev.minor = MISC_DYNAMIC_MINOR;
+        qos->pm_qos_power_miscdev.name = qos->name;
+        qos->pm_qos_power_miscdev.fops = &pm_qos_power_fops;
+
+        return misc_register(&qos->pm_qos_power_miscdev);
+}
+
+static int find_pm_qos_object_by_minor(int minor)
+{
+        int pm_qos_class;
+
+        for (pm_qos_class = 0;
+                pm_qos_class < PM_QOS_NUM_CLASSES; pm_qos_class++) {
+                if (minor ==
+                        pm_qos_array[pm_qos_class]->pm_qos_power_miscdev.minor)
+                        return pm_qos_class;
+        }
+        return -1;
+}
+
+/**
+ * pm_qos_requirement - returns current system wide qos expectation
+ * @pm_qos_class: identification of which qos value is requested
+ *
+ * This function returns the current target value in an atomic manner.
+ */
+int pm_qos_requirement(int pm_qos_class)
+{
+        int ret_val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        ret_val = pm_qos_array[pm_qos_class]->target_value;
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+        return ret_val;
+}
+EXPORT_SYMBOL_GPL(pm_qos_requirement);
+
+/**
+ * pm_qos_add_requirement - inserts new qos request into the list
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * This function inserts a new entry in the pm_qos_class list of requested qos
+ * performance charactoistics.  It recomputes the agregate QoS expectations for
+ * the pm_qos_class of parrameters.
+ */
+int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
+{
+        struct requirement_list *dep;
+        unsigned long flags;
+
+        dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
+        if (dep) {
+                if (value == PM_QOS_DEFAULT_VALUE)
+                        dep->value = pm_qos_array[pm_qos_class]->default_value;
+                else
+                        dep->value = value;
+                dep->name = kstrdup(name, GFP_KERNEL);
+                if (!dep->name)
+                        goto cleanup;
+
+                spin_lock_irqsave(&pm_qos_lock, flags);
+                list_add(&dep->list,
+                        &pm_qos_array[pm_qos_class]->requirements.list);
+                spin_unlock_irqrestore(&pm_qos_lock, flags);
+                update_target(pm_qos_class);
+
+                return 0;
+        }
+
+cleanup:
+        kfree(dep);
+        return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
+
+/**
+ * pm_qos_update_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ * @value: defines the qos request
+ *
+ * Updates an existing qos requierement for the pm_qos_class of parameters along
+ * with updating the target pm_qos_class value.
+ *
+ * If the named request isn't in the lest then no change is made.
+ */
+int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
+{
+        unsigned long flags;
+        struct requirement_list *node;
+        int pending_update = 0;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        list_for_each_entry(node,
+                &pm_qos_array[pm_qos_class]->requirements.list, list) {
+                if (strcmp(node->name, name) == 0) {
+                        if (new_value == PM_QOS_DEFAULT_VALUE)
+                                node->value =
+                                pm_qos_array[pm_qos_class]->default_value;
+                        else
+                                node->value = new_value;
+                        pending_update = 1;
+                        break;
+                }
+        }
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+        if (pending_update)
+                update_target(pm_qos_class);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
+
+/**
+ * pm_qos_remove_requirement - modifies an existing qos request
+ * @pm_qos_class: identifies which list of qos request to us
+ * @name: identifies the request
+ *
+ * Will remove named qos request from pm_qos_class list of parrameters and
+ * recompute the current target value for the pm_qos_class.
+ */
+void pm_qos_remove_requirement(int pm_qos_class, char *name)
+{
+        unsigned long flags;
+        struct requirement_list *node;
+        int pending_update = 0;
+
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        list_for_each_entry(node,
+                &pm_qos_array[pm_qos_class]->requirements.list, list) {
+                if (strcmp(node->name, name) == 0) {
+                        kfree(node->name);
+                        list_del(&node->list);
+                        kfree(node);
+                        pending_update = 1;
+                        break;
+                }
+        }
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+        if (pending_update)
+                update_target(pm_qos_class);
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
+
+/**
+ * pm_qos_add_notifier - sets notification entry for changes to target value
+ * @pm_qos_class: identifies which qos target changes should be notified.
+ * @notifier: notifier block managed by caller.
+ *
+ * will register the notifier into a notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+        int retval;
+
+        retval = blocking_notifier_chain_register(
+                        pm_qos_array[pm_qos_class]->notifiers, notifier);
+
+        return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
+
+/**
+ * pm_qos_remove_notifier - deletes notification entry from chain.
+ * @pm_qos_class: identifies which qos target changes are notified.
+ * @notifier: notifier block to be removed.
+ *
+ * will remove the notifier from the notification chain that gets called
+ * uppon changes to the pm_qos_class target value.
+ */
+int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
+{
+        int retval;
+
+        retval = blocking_notifier_chain_unregister(
+                        pm_qos_array[pm_qos_class]->notifiers, notifier);
+
+        return retval;
+}
+EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
+
+#define PID_NAME_LEN sizeof("process_1234567890")
+static char name[PID_NAME_LEN];
+
+static int pm_qos_power_open(struct inode *inode, struct file *filp)
+{
+        int ret;
+        long pm_qos_class;
+
+        pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
+        if (pm_qos_class >= 0) {
+                filp->private_data = (void *)pm_qos_class;
+                sprintf(name, "process_%d", current->pid);
+                ret = pm_qos_add_requirement(pm_qos_class, name,
+                                        PM_QOS_DEFAULT_VALUE);
+                if (ret >= 0)
+                        return 0;
+        }
+
+        return -EPERM;
+}
+
+static int pm_qos_power_release(struct inode *inode, struct file *filp)
+{
+        int pm_qos_class;
+
+        pm_qos_class = (long)filp->private_data;
+        sprintf(name, "process_%d", current->pid);
+        pm_qos_remove_requirement(pm_qos_class, name);
+
+        return 0;
+}
+
+static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
+                size_t count, loff_t *f_pos)
+{
+        s32 value;
+        int pm_qos_class;
+
+        pm_qos_class = (long)filp->private_data;
+        if (count != sizeof(s32))
+                return -EINVAL;
+        if (copy_from_user(&value, buf, sizeof(s32)))
+                return -EFAULT;
+        sprintf(name, "process_%d", current->pid);
+        pm_qos_update_requirement(pm_qos_class, name, value);
+
+        return  sizeof(s32);
+}
+
+
+static int __init pm_qos_power_init(void)
+{
+        int ret = 0;
+
+        ret = register_pm_qos_misc(&cpu_dma_pm_qos);
+        if (ret < 0) {
+                printk(KERN_ERR "pm_qos_param: cpu_dma_latency setup failed\n");
+                return ret;
+        }
+        ret = register_pm_qos_misc(&network_lat_pm_qos);
+        if (ret < 0) {
+                printk(KERN_ERR "pm_qos_param: network_latency setup failed\n");
+                return ret;
+        }
+        ret = register_pm_qos_misc(&network_throughput_pm_qos);
+        if (ret < 0)
+                printk(KERN_ERR
+                        "pm_qos_param: network_throughput setup failed\n");
+
+        return ret;
+}
+
+late_initcall(pm_qos_power_init);